swift - FileHandler 输出有更多缓冲区？

Question

我有以下代码:

func syncShellExec(path: String, args: [String] = []) {
    let process            = Process()
    process.launchPath     = "/bin/bash"
    process.arguments      = [path] + args
    let outputPipe         = Pipe()
    let filelHandler       = outputPipe.fileHandleForReading
    process.standardOutput = outputPipe
    process.launch()

    filelHandler.readabilityHandler = { pipe in
        let data = pipe.availableData
        if let line = String(data: data, encoding: String.Encoding.utf8) {
            DispatchQueue.main.sync {
                self.output_window.string += line
                self.output_window.scrollToEndOfDocument(nil)
            }
        } else {
            print("Error decoding data: \(data.base64EncodedString())")
        }
    }
    process.waitUntilExit()
    filelHandler.readabilityHandler = nil
}

如果达到约 330.000 个字符的回合数，输出将立即停止。有没有办法增加此操作的缓冲区？

Answer 1

有两个问题:

• 进程可能会在从管道中读取所有数据之前终止。
• 您的函数会阻塞主线程，因此 UI 最终会卡住。

类似于How can I tell when a FileHandle has nothing left to be read?您应该异步等待进程终止，并等待管道上的“文件结束”:

func asyncShellExec(path: String, args: [String] = []) {
    let process            = Process()
    process.launchPath     = "/bin/bash"
    process.arguments      = [path] + args
    let outputPipe         = Pipe()
    let filelHandler       = outputPipe.fileHandleForReading
    process.standardOutput = outputPipe
    process.launch()

    let group = DispatchGroup()
    group.enter()
    filelHandler.readabilityHandler = { pipe in
        let data = pipe.availableData
        if data.isEmpty { // EOF
            filelHandler.readabilityHandler = nil
            group.leave()
            return
        }

        if let line = String(data: data, encoding: String.Encoding.utf8) {
            DispatchQueue.main.sync {
                self.output_window.string += line
                self.output_window.scrollToEndOfDocument(nil)
            }
        } else {
            print("Error decoding data: \(data.base64EncodedString())")
        }
    }

    process.terminationHandler = { process in
        group.wait()
        DispatchQueue.main.sync {
            // Update UI that process has finished.
        }
    }
}